I checked out the 2010 and 2011 models... for all practical purposes they are the same bike.
18 speeds in the range on the Allegro will be just great for you as I understand it, Florida is mostly flat. You will have lower gears to go over highway overpasses or if you get off paved bicycle trails onto dirt trails.
The allegro is a good bike for city streets, general fitness riding, and commuting to work.
I don't think you will be able to install proper fenders but it doesn't rain much in Florida and I don't expect you will be cycling in hurricanes.
You won't be able to install a regular rear rack, but you will be able to use a rack that attached to your seat post. This provides a place to carry a pump, spare tire, and a couple tools. Or you could use a handlebar bag.
The Allegro is designed for casual riding including errands around town and general fitness, the occasional trip to the beach.
There are other specialized bicycles for road racing, long distance touring, mountain biking, off road cross country riding, downhill racing, etc... The allegro is not designed for these purposes but I assume you are not planning this right away.
I think it is an excellent choice for someone wanting to get back into biking without having a special purpose in mind.
Welcome to the Forum.
And happy cycling.